70-300 Problem - Focusing error

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giantxtc
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70-300 Problem - Focusing error

Unread post by giantxtc »

OK hello again I haven't really posted much on here but I do read a lot and I have to thank you guys/girls again for that.

Well I'm having a problem with my 70-300G lens on my A700. I was using the lens outside today and when I was zoomed out there were no problems but when I tried zooming in I heard a strange sound something I hadn't heard before it was a clicking or tapping sound. It was pretty fast and then I noticed the focus window wasn't moving. Something is jammed up and I'm lost. It doesn't happen all them time meaning it comes free but it keeps sticking.

The lens actually made a whooshing sound once and continued even after I turned the camera off!! I kind of stopped right there but I did notice that when the clicking sound was happening if I turned off my camera the focus window did not return to infinity it stayed where it was.

I also noticed that the focus ring when set in MF did not do much at all it seems to be barely focusing the lens. I don't know very much about the construction of the lens but it seems like something is holding up the focus mechanism. Very strange anyone experience this here? I checked all the contacts and tried other lenses they work fine only the G-

Thanks-
Chris
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Dusty
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Re: 70-300 Problem - Focusing error

Unread post by Dusty »

Chris,

Not to put a scare into you, but it sounds like a stripped gear. I'd get it to Sony Repairs before it messed up the camera to boot!

Dusty
giantxtc
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Re: 70-300 Problem - Focusing error

Unread post by giantxtc »

Thanks! I just got off the phone with support. I'm sending it to Laredo tomorrow I was told I'd have it back in 7-10days. Hmm stripped gear that's interesting I wonder what causes that? Hopefully it's not something I did! I really haven't had a chance to use the lens that much over the last month I've owned it (too cold here in the midwest for that kind of reach!)

I hope I didn't hurt the A700, I put it back on the camera when I was talking to the support staff and when I turned it off the camera kept winding like it was trying to reset the focus and it wouldn't budge. Scary it did this for 5-10 seconds after the camera was off!

I guess I'm going to have my first experience with sony support and alpha repair... Too bad I have to pay shipping but what are you gonna do...

thanks again
chris
Javelin
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Re: 70-300 Problem - Focusing error

Unread post by Javelin »

This lens has a clutch for the focus ring. it sounds like the clutch is cracked. Also i think this lens can't focus from the camera motor, the socket for the drive pin on the lens looks like it's made to trap and hold the drive pin to prevent it from turning. where the other lenses have a bushed slotted rotating element for the drive pin to fit into.
giantxtc
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Re: 70-300 Problem - Focusing error

Unread post by giantxtc »

Thanks Javelin- You must have some pretty extensive knowledge on the design of this lens. I just hope I can get it back ASAP with no problems. I'm not sure what would cause the clutch to crack? I really take great care of all my equipment, this lens has been in my bag and handled with care. I haven't found any other information of this happening so I'm guessing it's pretty rare. I'm not sure what would have caused this... The camera was set to continuous AF at the time it happened first.
Javelin
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Re: 70-300 Problem - Focusing error

Unread post by Javelin »

hah! no special knowledge when I got mine I was surprized the focus ring wasn't directly linked is all and was comparing it to myother lenses. My 28-135 is also rear focusing but doesn't have this sort of clutch.
giantxtc
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Re: 70-300 Problem - Focusing error

Unread post by giantxtc »

:lol: :lol:
David Kilpatrick
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Re: 70-300 Problem - Focusing error

Unread post by David Kilpatrick »

Before you send the lens to Laredo, do one test - try a different, fully charged, battery in the camera. I am not suggesting this is likely to be the problem, it does sound as if you may have a fault inside the lens, but all SSM and similar lenses are very dependent on the condition of the battery to deliver power when needed. Therefore, it is always worth checking not only a fully charged battery, but also a fully charged DIFFERENT battery if you have two.

David
giantxtc
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Re: 70-300 Problem - Focusing error

Unread post by giantxtc »

Thanks David, unfortunately I already shipped it today... I really wanted to get it out so I can get it back! Hopefully it has nothing to do with operator error. :oops:

The only thing I would be concerned is maybe I turned the focus ring when trying to zoom in, due to them being switched around. Other than that I don't think I had anything to do with this. And if that was the case I didn't notice anything at the time.

Chris
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Re: 70-300 Problem - Focusing error

Unread post by Javelin »

I do this all the time when I switch lenses for the first few minutes. I really need to put this lens side by side with my BBC because I think it isn;t as sharp s it should be or at least it seems I get better results with my BBC
giantxtc wrote:The only thing I would be concerned is maybe I turned the focus ring when trying to zoom in, due to them being switched around. Other than that I don't
think I had anything to do with this. And if that was the case I didn't notice anything at the time.

Chris
giantxtc
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Re: 70-300 Problem - Focusing error

Unread post by giantxtc »

Okay I got the lens back today and have to say I'm pretty happy. Everything works great and looks great. It did come with a slip but I'm not sure exactly what the description means other than what it says.

Maybe someone with more technical experience can explain, this is how it reads:

A153... Middle Lens Barrel 1 1
3299... 1st - F Linkage Barrel 1 1
Constant Weak/Excess Pictr
Replaced Parts
Replaced Parts

There were no charges and I got it back today 4/6 Mailed it 3/24 (Not bad at all)

Chris
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Dr. Harout
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Re: 70-300 Problem - Focusing error

Unread post by Dr. Harout »

Can't figure it out but congratulations for getting it fixed. :D
A99 + a7rII + Sony, Zeiss, Minolta, Rokinon and M42 lenses

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giantxtc
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Re: 70-300 Problem - Focusing error

Unread post by giantxtc »

Thanks, I guess all that matters is it works!
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